Just get the lightest gauge strings you can find that will fit it and tune them up. Lighter string = less tension, so you can tune them higher (tighter) without breaking them or having very tight strings.

It's tuned an octave higher than a regular bass, so (assuming four strings) the notes are the same as the bottom four on a guitar. However, the tone and spacing will make the playing style different - it's not exactly the same as playing basslines on a guitar.